Abstract Pressure arches form in and affect the stability of fractured rock reinforced by rockbolts; however, no direct indicator of pressure arch presently exists. A sophisticated model was developed using the 3D particle flow code (PFC3D) to perform gravel bolting tests that allow pressure arches visualization to investigate their formation and influencing factors. The results suggested that a pressure arch can be formed in bolted gravel through interlocking between gravel particles. The whole load of the gravel contained in the filling box is carried by the pressure arch. The formation conditions of a pressure arch are obtained. The rockbolt spacing should be less than 2.5 times the average gravel size. The thickness of the gravel pack should not be less than 2.5 times the rockbolt spacing. Besides, the thickness of the gravel pack should be ~ 0.6 times the side length of the gravel pack. The plate size should not be less than 0.6 times the rockbolt spacing. The formation of a pressure arch is insensitive to the rockbolt elastic modulus. The specific function of rockbolts in bolted gravel is to help form a pressure arch by exerting supporting and surface-retaining effects to stabilize the gravel particles below the pressure arch. Some suggestions were made for rockbolt support in extremely fractured rock in mining roadways.

中文翻译：

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锚固碎石板压力拱形成的数值研究

摘要 压力拱在岩栓加固裂隙岩体中形成并影响其稳定性；然而，目前不存在压力拱的直接指标。使用 3D 粒子流代码 (PFC3D) 开发了一个复杂的模型来执行砾石锚固测试，允许压力拱可视化以研究其形成和影响因素。结果表明，通过砾石颗粒之间的互锁，可以在螺栓连接的砾石中形成压力拱。充填箱内砾石的全部荷载由压拱承担。得到了压力拱的形成条件。锚杆间距应小于平均砾石尺寸的 2.5 倍。砾石充填厚度不应小于锚杆间距的2.5倍。除了，砾石充填的厚度应为砾石充填边长的 0.6 倍。板尺寸不应小于锚杆间距的0.6倍。压力拱的形成对锚杆弹性模量不敏感。锚杆在锚固砾石中的具体功能是通过施加支撑和表面保持作用来稳定压力拱下方的砾石颗粒，从而帮助形成压力拱。对矿山巷道极度破碎岩层中的锚杆支护提出了一些建议。锚杆在锚固砾石中的具体功能是通过施加支撑和表面保持作用来稳定压力拱下方的砾石颗粒，从而帮助形成压力拱。对矿山巷道极度破碎岩石中的锚杆支护提出了一些建议。锚杆在锚固砾石中的具体功能是通过施加支撑和表面保持作用来稳定压力拱下方的砾石颗粒，从而帮助形成压力拱。对矿山巷道极度破碎岩石中的锚杆支护提出了一些建议。